The long-term objective for this NRSA training grant in nursing research is to support the applicant's training as a nurse scientist committed to understanding and reducing reproductive health disparities in the Mexican-origin population in the United States. Reducing and eliminating health disparities is emphasized in the National Institute of Nursing Research's strategic plan and there are significant reproductive health disparities among Mexican-origin adolescent females in the U.S., including an increased risk for childbirth. Previous research on reproductive health behavior in adolescents has focused on individual and familial risk factors and has not addressed the heterogeneity of Latinos, including country of origin and immigrant status, which has limited exploration of the influence of structural factors. Furthermore, the role of culture and how it influences the reproductive health behavior of adolescents remains poorly understood. This training plan will provide support for a research project to investigate how cultural constructions of gender and sexuality mediate the relationship between structural factors and reproductive health behaviors in Mexican- origin adolescent females through three specific aims: (1) to investigate how structural factors (i.e., community level poverty, residential segregation) influence reproductive health behaviors (i.e., age at first birth, age at first sex, contraceptive use) across three immigrant generations of Mexican-origin adolescent females. This aim will be met through a secondary data analysis of The National Longitudinal Study of Adolescent Health. (2) To explore how cultural constructions of gender and sexuality differ across three immigrant generations of Mexican-origin adolescent females. This aim will be met through semi-structured life history interviews in a Mexican community in Denver, Colorado. (3) To explain how cultural constructions of gender and sexuality mediate the relationship between structural factors and reproductive health behaviors across three immigrant generations of Mexican-origin adolescent females. This aim will be met through the integration and analysis of the quantitative and qualitative data. This training plan i interdisciplinary, bio-behavioral, and utilizes a multi- level mixed quantitative and qualitative approach, which are strategies endorsed by NINR to improve nursing research. With the rapid growth of the Mexican-origin population in the U.S., coupled with significant health and economic disparities across the lifespan, this research project will address the gaps in the literature, is timely, and has potential to provide evidence for interventions that can reduce health disparities, improve population health, and increase the quality of life for Mexican-origin persons in the U.S.